GB2104916A - Grain-oriented electromagnetic steel sheet and process for producing the same - Google Patents

Grain-oriented electromagnetic steel sheet and process for producing the same Download PDF

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GB2104916A
GB2104916A GB08222595A GB8222595A GB2104916A GB 2104916 A GB2104916 A GB 2104916A GB 08222595 A GB08222595 A GB 08222595A GB 8222595 A GB8222595 A GB 8222595A GB 2104916 A GB2104916 A GB 2104916A
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grain
steel sheet
electromagnetic steel
oriented electromagnetic
copper
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Katsuro Kuroki
Shozaburo Nakashima
Toshiya Wada
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Nippon Steel Corp
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Nippon Steel Corp
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    • C—CHEMISTRY; METALLURGY
    • C21—METALLURGY OF IRON
    • C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
    • C21D8/00—Modifying the physical properties by deformation combined with, or followed by, heat treatment
    • C21D8/12—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of articles with special electromagnetic properties
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C38/00—Ferrous alloys, e.g. steel alloys
    • C22C38/02—Ferrous alloys, e.g. steel alloys containing silicon
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
    • H01F1/00—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties
    • H01F1/01—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials
    • H01F1/03—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials characterised by their coercivity
    • H01F1/12—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials characterised by their coercivity of soft-magnetic materials
    • H01F1/14—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials characterised by their coercivity of soft-magnetic materials metals or alloys
    • H01F1/16—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials characterised by their coercivity of soft-magnetic materials metals or alloys in the form of sheets
    • H01F1/18—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials characterised by their coercivity of soft-magnetic materials metals or alloys in the form of sheets with insulating coating
    • C—CHEMISTRY; METALLURGY
    • C21—METALLURGY OF IRON
    • C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
    • C21D8/00—Modifying the physical properties by deformation combined with, or followed by, heat treatment
    • C21D8/12—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of articles with special electromagnetic properties
    • C21D8/1216—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of articles with special electromagnetic properties the working step(s) being of interest
    • C21D8/1233—Cold rolling
    • C—CHEMISTRY; METALLURGY
    • C21—METALLURGY OF IRON
    • C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
    • C21D8/00—Modifying the physical properties by deformation combined with, or followed by, heat treatment
    • C21D8/12—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of articles with special electromagnetic properties
    • C21D8/1244—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of articles with special electromagnetic properties the heat treatment(s) being of interest
    • C21D8/1266—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of articles with special electromagnetic properties the heat treatment(s) being of interest between cold rolling steps

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  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • Materials Engineering (AREA)
  • Mechanical Engineering (AREA)
  • Metallurgy (AREA)
  • Organic Chemistry (AREA)
  • Dispersion Chemistry (AREA)
  • Power Engineering (AREA)
  • Electromagnetism (AREA)
  • Manufacturing & Machinery (AREA)
  • Thermal Sciences (AREA)
  • Crystallography & Structural Chemistry (AREA)
  • Manufacturing Of Steel Electrode Plates (AREA)
  • Soft Magnetic Materials (AREA)

Description

1 GB 2 104 916 A 1
SPECIFICATION
Grain-oriented electromagnetic steel sheet and process for producing the same The present invention relates to a grain-oriented electromagnetic steel sheet or strip having a low watt loss and a high magnetic flux density and also to a process for producing such grain-oriented electromagnetic steel sheet or strip.
The descriptions hereinunder relate mainly to a grain-oriented electromagnetic steel sheet. A grain-oriented electromagnetic steel sheet is used as a soft magnetic material for the core of transformers and other electrical machinery and apparatuses. As magnetic properties of a grainoriented electromagnetic steel sheet, the exciting characteristic must be excellent and the watt loss must be low. In order to obtain a grain-oriented electromagnetic steel sheet having excellent magnetic 10 properties, it is important to align the <001 > axis of the crystals of a grain-oriented electromagnetic steel sheet in the rolling direction at a high degree of orientation, the axis being the easy direction of magnetization. In addition to this, the grain size, resistivity, and surface coating of a grain-oriented electromagnetic steel sheet exert a great influence on the magnetic properties. The development of a single-stage cold-rolling process has drastically enhanced the degree of orientation, and grain-oriented 15 electromagnetic steel sheets presently being produced exhibit a magnetic flux density amounting to approximately 96% of the theoretical value. Due to enhancement of the degree of orientation, watt loss can be drastically decreased. Nevertheless, a further decrease of watt loss is not possible only by enhancement of the degree of orientation; rather, technical means for increasing the resistivity mentioned above and for refining the secondary recrystallized grains are necessary to attain such further 20 decrease of watt loss.
A technical means for refining the secondary recrystallized grains is particularly important in the single-stage cold-rolling process, in which the final reduction ratio is high, since it is probable that in this process watt loss may not be reduced in porportion to the enhanced degree of orientation achieved in the single-stage cold-rolling process. More specifically, the positive effect of enhancement of the degree 25 of orientation tends to be neutralized by the negative effect of increment of the size of the secondary recrystallized grains with the result that a decrease in watt loss cannot be expected. This tendency is more prominent with increase in thickness of grain-oriented electromagnetic steel sheet.
Japanese Unexamined Patent Publication No. 53-134722 (1978) proposes to incorporate tin into a silicon steel material containing a minor amount of aluminum so as to attain refinement of the 30 secondary recrystallized grains while maintaining a high degree of orientation.
The incorporation of tin into the silicon steel material mentioned above, however, involves a problem in that tin may deteriorate the surface coating of a grain- oriented electromagnetic steel sheet.
As is well known, the surface coating of a grain-oriented electromagnetic steel sheet not only plays an important role in insulating the laminated sheet sections of a transformer from each other but also 35 imparts tension to said steel sheet due to the difference in the thermal expansion coefficient between said surface coating and said steel sheet, with the result that watt loss is greatly decreased. Therefore, although refinement of the secondary recrystallized grains may be attained by incorporating tin into the silicon steel material, watt loss cannot be satisfactorily decreased due to deterioration of the surface coating mentioned above.
Japanese Unexamined Patent Publication No. 49-72118 (1974) discloses to incorporate copper alone into steel composition containing aluminum. However, the incorporation of copper alone disadvantageously results in coarsening of secondary recrystallized grains.
It is an object of the present invention to refine the secondary recrystallized grains of a grain oriented electromagnetic steel sheet or strip by providing such steel sheet or strip with a novel composition by which the surface coating of the steel sheet or strip is improved, the secondary recrystallized grains are refined, and the grain-orientation is not impaired.
It is another object of the present invention to provide a process for producing a grain-oriented electromagnetic steel sheet or strip in which the secondary recrystallized grains are refined and, further, the properties of the surface coating are improved, with the result that low watt loss can be ensured 50 particularly at a high magnetic flux density.
In accordance with the objects of the present invention, there is provided a grain-oriented electromagnetic steel sheet or strip having a low watt loss and a high magnetic flux density, characterized in that it contains from 2.5% to less than 4.0% of silicon, from 0.03% to less than 0. 15% of manganese, from 0.03% to less than 0.5% of tin, and from 0.02% to less than 0.3% of copper, the 55 remaining percentage being iron and unavoidable impurities.
impurities.
In accordance with the objects of the present invention, there is also provided a process for producing a grain-oriented electromagnetic steel sheet or strip having a low watt loss and a high magnetic flux density, characterized in that a silicon steel material, containing not more than 0.085% of 60 carbon, from 2.5% to 4.0% of silicon, from 0.03% to 0.15% of manganese, from 0.010% to 0.050% of sulfur, from 0.010% to 0.050% of acid-soluble aluminum, and from 0.0045% to 0.012% of nitrogen and additionally containing from 0.03% to 0.5% of tin and from 0.02% to 0. 3% of copper is hot-rolled, precipitation-annealed, cold-rolled at a final reduction ratio of not less than 65%, decarburization- 2 GB 2 104 916 A annealed, and final-annealed.
A grain-oriented electromagnetic steel sheet or strip may be provided with a surface coating which preferably comprises M91S'04 and which preferably has a thickness of about 3 microns.
The preferable properties of a grain-oriented electromagnetic steel sheet having thickness of from 5 0.35 to 0.15 mm according to the present invention are:
Watt loss W11150): 1.00 - 0.90 watts/kg Watt loss (W15,11): 0.76 - 0.67 watts/kg ASTM grain size: No. 4 - No. 7 Magnetic flux density (B,): 1.88 (1.96 tesla The present invention is characterized by incorporating into molten silicon steel copper which is 10 effective for the formation of a good surface coating of a grain-oriented electromagnetic steel sheet. In other words, conventional methods for improving such surface coating reside in the incorporation of an element into the annealing separator. However, such conventional methods cannot fundamentally improve the surface coating of a grain-oriented electromagnetic steel sheet which contains tin because an element which is incorporated into the surface coating cannot prevent the surface coating from being influenced by the oxide film which is formed on the steel sheet during decarburization-annealing. Based on the present inventors' concept described above, the present inventors incorporated copper into molten silicon steel in addition to tin in an attempt to utilizethe favorable effects of copper. Since the secondary recrystallized structure is considerably influenced by the incorporation of copper, the incorporation of copper has usually been avoided. Fortunately, in the present invention, when copper 20 was incorporated in addition to tin the favorable effects of both elements were utilized and the unfavourable effects of copper were neutraliazed by the favorable effects of tin and vice versa.
More specifically, copper is a very excellent element which can be utilized in the formation of the surface coating of a grain-oriented electromagnetic steel sheet, and the qualities, especially the adhesive property, of such a surface coating are improved by the copper. Copper, however, tends to coarsen the 25 secondary recrystallized grains. Contrary to this, tin contributes to refinement of the secondary recrystallized grains but it deteriorates the surface coating of a grain- oriented electromagnetic steel sheet. According to the present invention, the advantages resulting from the combined use of copper and tin are maintained and the disadvantages resulting from the combined use of copper and tin are eliminated, this phenomenon being a discovery by the present inventors.
The present invention is now quantitatively described.
First, the composition of a silicon steel material, which is the starting material of the process according to the present invention, is described. The silicon steel material contains as basic elements not more than 0.085% of carbon, from 2.5% to 4.0% of silicon, from 0.010% to 0.050% of acid-soluble aluminum, from 0.03% tob.1 5% of manganese, and from 0.010% to 0.050% of sulfur and also contains as characteristic elements from 0.03% to 0.5% of tin and from 0. 02% to 0.3% of copper.
The carbon content is limited to not more than 0.085% because the decarburization-annealing period is long when the carbon bontent exceeds 0.085%. A silicon content of at least 2.5% is necessary for attaining low watt loss. However, a silicon content exceeding 4.0% disadvantageously renders cold-rolling difficult. Secondary recrystallization is not stabilized when the content of acid-soluble 40 aluminum does not fall within the range of from 0.010% to 0.050%.
Manganese and sulfur are necessary for forming MnS. An dppropriate amount of manganese is from 0.03% to 0.15% and a preferable amount of manganese is from 0.05% to 0. 10%. When the sulfur content exceeds 0.05%, desulfurization during purification-annealing becomes difficult. On the other hand, a sulfur content of less than 0.01 % is too low to form a satisfactory amount of MnS, MnS being 45 one of the inhibitors.
Tin in an amount of less than 0.03% is too low to effectively attain refinement of the secondary recrystallized grains. On the other hand, when the tin content exceeds 0. 5%, the operating efficiency during rolling and pickling is deteriorated. The combined incorporation of tin and copper also causes the operating efficiency to deteriorate. The preferable tin content is from 0. 05% to 0.20%.
Copper in an amount of less than 0.02% is too small to improve the surface coating of a grain oriented electromagnetic steel sheet while copper in an amount exceeding 0.3% is undesirable in the light of the magnetic properties of a grain-oriented electromagnetic steel sheet. The preferable copper content is from 0.05% to 0. 15%.
The proportion of tin to copper exerts an influence on the surface coating and on refinement of the 55 secondary recrystallized grains of a grain-oriented electromagnetic steel sheet.
The present invention is hereinafter explained with reference to the drawings, wherein:
Figure 1 illustrates how the proportion of tin to copper contents exerts an influence on the watt loss and grain size of a grainoriented electromagnetic steel sheet, as does tension generated due to the surface coating of a grain-oriented electromagnetic steel sheet; 3 GB 2 104 916 A 3 Fig. 2A is an optical microscope photograph showing the cross section of a grain-oriented electromagnetic steel sheet having a surface coating thereon and containing tin only; Fig. 213 is an optical microscope photograph showing the cross section of a grain-oriented electromagnetic steel sheet having a surface coating thereon containing both tin and copper; and Fig. 3 illustrates the relationships between watt loss M171.. and W15150) and magnetic flux density (13J with regard to a conventional grain- oriented electromagnetic steel sheet having a high magnetic flux density (a) and the grain-oriented electromagnetic steel sheet of the present invention (b).
Figure 1 shows the proportion of the tin to copper contents, which proportion was varied, in the silicon steel materials tested. The tested silicon steel materials contained 0.056% of carbon, 2.96% of silicon, 0.076% of manganese, 0.025% of sulfur, 0.027% of acid-soluble aluminum, 0.0075% of nitrogen, and 0.2% of tin. In addition, the content of copper was varied so as to give the proportion of tin to copper shown by the abscissa. In the figure W17150 is the watt loss at a magnetic flux density of 1.7 tesla and 50 Hz, and the grain size is expressed according to the ASTM standard at a magnification of x 1. The tension generated due to the surface coating was obtained by calculating the amount of deflection of the grain-oriented electromagnetic steel sheets having a surface coating on only one of the 15 surfaces thereof. The deflection was brought about by applying on the final-annealed steel sheets a coating liquid mainly composed of phosphoric acid, chromic acid anhydride and aluminum phosphate, subjecting the sheets to flattening-annealing, and removing the surface coating from said one surface of the steel sheets with acid. 20 Watt loss M17150) is very low when the proportion of tin to copper is in the range of from 1:0.5 to 20 1:1. In this range, an appreciable decrease in grain size due to tin and an appreciable increase in the tension of the surface coating are simultaneously attained. A preferable proportion of tin to copper is approximately 1:0.75. The watt 1OSS M17,10) tends to be very low, and the tension generated by the surface coating and the grain size tend to increase and decrease, respectively, when the proportion of the tin to copper content is in the range of from 1:0.5 to 1:1 not only in the case of a tin content of 0.2% but also in the case of a different tin content. It is not clear why copper is effective for the formation of a good surface coating on a grainoriented electromagnetic steel sheet. In order to form a good surface coating on a grain-orented electromagnetic steel sheet, the properties of an oxide film, which is formed during decarburization- 30 annealing and which underlies the surface coating, must be good. As the results of the present inventors' ' experiment showed, the thickness of the surface coating was more uniform when tin and copper were incorporated into silicon steel material in combination than when only tin was incorporated.
Presumably, the oxide film mentioned above comprises, in addition to oxides of iron, silicone, and aluminum, oxides of tin and copper, the copper oxide improving the properties of the oxide film and 35 contributing to the formation of a good surface coating.
In Fig. 2A, the silicon steel material contained 3% of silicon and 0.2% of tin while in Fig. 213 the silicon steel material contained 3% of silicon, 0.2% of tin, and 0.11 % of copper, After final-annealing, surface coating was formed on each grain-oriented electromagnetic steel sheet. A strap was attached to the surface coating of each steel sheet so that the surface coating could be observed with an optical 40 microscope. Each grain-oriented electromagnetic steel sheet having a surface coating and a strap thereon was cut into a cross section which was observed at a magnification of 1000. In Fig. 2A, the surface coating was discontinuous in several places. In Fig. 213 the thickness of the surface coating was uniform, indicating that the incorporation of copper drastically improved the uniformity of the surface coating.
In addition to the carbon content, manganese content, tin content, and copper content described hereinabove, from 0.0045% to 0.012% of nitrogen, which is one of the indispensable elements, must be contained in silicon steel material so as to effectively precipitate AIN, AIN being another inhibitor.
Silicon steel material may further contain unavoidable impurities, such as nickel, chromium, and titanium, in a minor amount.
Next, a process for producing a grain-oriented electromagnetic steel sheet according to the present invention will be described.
Silicon steel material containing the elements described above may be produced by any known melting, ingot- or slab-making, and rough-rolling methods. Such silicon steel material is then hot-rolled by means of a conventional method so as to produce a hot-rolled coil. Then the hot-rolled coil is 55 subjected to either single-stage cold-rolling or double-stage cold- rolling including intermediate annealing, the final thickness being obtained during single-stage or double-stage cold-rolling. A high final cold-rolling reduction ratio of from 65% to 95%, preferably from 80% to 92%, is necessary in the final cold-rolling step so as to ensure a high magnetic flux density of a grain-oriented electromagnetic steel sheet.
When the cold-rolling reduction ratio is less than 65%, a high magnetic flux density cannot be obtained. On the other hand, when the cold-rolling reduction ratio exceeds 95%, growth of secondary recrystallized grains is unstable. A cold-rolling reduction ratio at a step(s) other than the final cold-rolling sten is not snecified.
The magnetic properties of a grain-oriented electromagnetic steel sheet, which are improved due65 4 GB 2 104 916 A to the combined incorporation of tin and copper, can be further improved when aging at a temperature of from 3001C to 600'C is carried out between the cold-rolling passes in accordance with the disclosures of Japanese Examined Patent Publication No. 54-13866 (1979) and Japanese Examined Patent Publication No. 54-29182 (1979). In addition, as is disclosed in Japanese Examined Patent
Publication No. 40-15664, the precipitation of AIN may be controlled by carrying out annealing at a temperature of from 9500C to 12000C for from 30 seconds to 30 minutes, followed by rapid cooling.
A sheet which has been subjected to cold-rolling so that a final sheet thickness is obtained is subjected to conventional clecarburizationannealing. During decarburization-annealing, not only do decarburization and primary recrystallization of the cold-rolled sheet take place but also an oxide film, which is necessary for the application of a surface coating, is formed on the cold-rolled sheet. Therefore, 10 not only do the conditions of decarburization-annealing greatly influence the properties of the surface coating, which is applied on a grain-oriented electromagnetic steel sheet after finalannealing, but they also influence the magnetic properties of a grain-oriented electromagnetic steel sheet. Preferable decarburization- annea ling conditions are: an annealing temperature of from 8001C to 900OC; holding the annealing temperature for from 30 seconds to 10 minutes; and a protective atmosphere for 15 annealing comprising wet hydrogen, wet nitrogen, or a mixture of wet hydrogen and nitrogen.
After deca rbu rization-a n nea ling, an annealing separator is applied on the resultant steel sheet so as to prevent sticking of said sheet during final annealing and as a preparatory step in the formation of the surface coating of a grain-oriented electromagnetic steel sheet. The annealing separator is not restricted to a specific composition but is preferably composed mainly of MgO and Ti02. Final annealing 20 is carried out at a temperature of 11 001C or higher for 5 hours or longer in a hydrogen- or hydrogen containing protective atmosphere. During final annealing, an inorganic coating is formed on the surface of the resultant grain-oriented electromagnetic steel sheet.
Subsequently, a coating liquid mainly composed of phosphoric acid, chromic acid anhydride, and aluminum phosphate is applied on the grain-oriented electromagnetic steel sheet, which is then 25 subjected to flattening-annealing, with the result that the coating liquid imparts strength to the resultant surface coating and tension to the surface of the grain-oriented electromagnetic steel sheet, this strength and tension being superior to the strength and tension of the inorganic coating mentioned above.
Now, the composition of and several properties of a grain-oriented electromagnetic steel sheet 30 according to the present invention are described.
The grain-oriented electromagnetic steel sheet of the present invention contains from 2.5% to less than 4.0% of silicon, from 0.03% to less than 0. 15% of manganese, from 0. 03% to less than 0.5% of tin, and from 0.02% to less than 0.3% of copper, the remaining percentage being iron and unavoidable impurities. Silicon, which increases the resistivity of steel, manganese, which contributes to the growth 35 of the secondary recrystailized grains, tin, which contributes to refinement of the secondary recrystallized grains, and copper, which improves the quality of the surface coating, remain in the grainoriented electromagnetic steel in virtually the same amounts as in a silicon steel material although the content of each of these elements is slightly decreased during the process of producing a grain-oriented electromagnetic steel sheet. The other elements, such as carbon, sulfur, nitrogen, and aluminum, remain 40 in the final product, i.e., the grain- oriented electromagnetic steel sheet, in trace amounts since they are removed during the annealing steps. In addition, these elements are merely impurities of the grainoriented electromagnetic steel sheet since they play a roll during the process of producing the grainoriented electromagnetic steel sheet. The values of the final product can be enhanced by decreasing the content of these impurities as much as possible.
The grain-oriented electromagnetic steel sheet of the present invention has a small grain size in the range of from No. 4 to 7 according to the ASTM standard (at a magnification of x 1) without the degree of orientation being decreased. The grain size mentioned above is at least one size smaller than the conventional grain size according to the ASTM standard. The tension generated due to the surface coating in the present invention is equivalent to the conventional one.
Watt loss of a grain-oriented electromagnetic steel sheet of the present invention is very low, and such very low watt loss can be attained obviously when the sheet thickness is great and even when the sheet thickness is 0.25 mm or less and hence small. According to the present invention, it is possible to stably produce a grain-oriented electromagnetic steel sheet having a very low watt loss not only when the sheet thickness is great but also when the sheet thickness is small, i.e. from 0.15 to 0.20 mm. 55 The present invention is hereinafter explained by way of examples.
EXAMPLE 1
In Fig. 3, conventional grain-oriented electromagnetic steel sheets (a) having a high magnetic flux density (hereinafter simply referred to as the products (a)) were produced by using AIN as the main inhibitor while grain-oriented electromagnetic steel sheets (b) having a high magnetic flux density (hereinafter simply referred to as the products (b)) were similarly produced by using AIN as the main inhibitor and incorporating tin and copper into the molten steel.
The composition of the products (a) and (b) are given in Table 1.
- 60 GB 2 104 916 A 5 1 TABLE 1
Products SiN Mn(%) SnN CUM ASTM Grain-size Other Elements (X 1) Iron and minor amounts of At, C, (a) 2.90-3.0 0.070-,0.075 0.01 0.01 N, S, and the like 3 A (b) 2.90,4.0 0.070-0.075 Q08-0.18 0.06-0.10 01 5,5 As is apparent from Fig. 3, the watt loss of the products (b) is lower than the watt loss of the products (a,). In addition, the watt- lossdifferenc'e between the products (a) and the products (b) becomes greater at a higher magnetic flux density, indicating that the reduction in watt loss due to 5. reftnement of the secondary recrystallized grains becomes mdre appreciable when the magnetic flux k density of the grii?- oriented electromagnetic steel sheet is high.
EXAMPLE 2 The three ingots produced contained 0.056% of carbon, 3.05% of silicon, 0.075% of manganese, 0.023% of sulfur, 0.027% of acid-soluble alumhum, and 0.080% of nitrogen. One of the ingots actOitionally contained 0.15% of tin, and another ingot additionally contained 0.15% of tin and 0.09% of copper. The composition of each oi the three ingots is given in Table 2.
TABLE 2
Ingot CM SiM Mn(%) SM 501AI(%) N(%) Sn(%) cu- (%) (d) 0.056 3.05 0.078 0.023 0.027 0:080 (C) 0.056 3.05 0.078 0.024 0.027 0.078 0.15 - (f) 0.056 3.05 0.078 0.023 0.026 0.078 0.15 0.09 Tese ingots were hot-rolled after being heated to 13500C so as to obtain hot-rolled sheets having a tlickness of 2.3 mm. Subsequently, prbcipitation annealing was carried out at 11 500C for 2 minutes, followed by rapid cooling in hot water having a temperature of 1 Op'C. The hot-rolled sheets is were then pickled and cold-rolled so as to reduce the sheet thickness to 0,30 mm. During cold-rolling, aging at a temperature of 2501C for 3 minutes was carried out between the cold-rolling passes.
Subsequently, decarburization-annealing was carried out at a temperature of 8500C for 150 seconds in an atmosphere consisting of 75% hydrogen and 25% nitrogen and having a dew point of 620C. An annealing separator consisting of a mixture of MgO and Ti02 WaS applied on the decarburization- 20 annealed steel sheets.and then final-annealing was carried out at a temperature of 12000C for 20 hour%.) Subsequently, a coating liquid, which was mainly composed of phosphoric acid. chromic acid anhybride, and aluminum phosphate, was applied on the final-annealed steel sheets. which were then subjected to flattening-annealing.
The magnetic properties and grain size of the final products (d), (e), and (f) which were produced 25 using the ingots (d), (c), and (f), respectively, were measured. In addition, the appearance, adhesion property, and tension of the sAce coatings of each of the final products were determined. In determining the adhesion property, test samples of the final products (d), (e), and (f) were bent argund a rod 20 mm in diametr and then the surface coating of each sample was examined for peeling. In v -determining the'tension, te surface coating was removed from one lurface of each of the final products 30 (0), (e), and (f) and then the deflection was measured.
The following table showsithe properties of the final products (d), (e). and (f).
t 6 GB 2 104 916 A 6 TABLE 3
Magnetic Properties Grain Size Property of Surface Coating Final W '17/50 Adhesion Tension Product B, (T) (W/Kg) ASTM No. x 1 Appearance Property (g/MMI) (d) 1.94 1.03 3 Good 0 650 Thin as (e) 1.94 1.02 5.5 a whole X 260 (f) 1.94 0.98 5 Good 0 650 The composition of each of the final products (d), (e), and (f) is shown in Table 4.
TABLE 4
Final Product SiN Sn(%) CuM Other Elements Iron and minor amounts of AI, C, N, S and (d) 2.95 0.070 - the like Iron and minor amounts of AI, C, N, S and (e) 2.95 0.070 0.14 - the like Iron and minor amounts of AI, C, N, S and (f) 2.95 0.070 0.14 0.08 the like EXAMPLE 3
The three ingots (g), (h), and (i) produced contained 0.058% of carbon, 3. 18% of silicon, 0.075% 5 of manganese 0.025% of sulfur, 0.028% of acid-soluble aluminum, 0.083% of nitrogen, and 0. 13% of tin. The copper content of the three ingots was as follows: ingot (g), 0. 03% of copper; ingot (h), 0.08% of copper; and ingot (i), 0.20% of copper.
These ingots were hot-rolled and subsequently were precipitation-a n nea led at 11 501C for 30 seconds, followed by rapid cooling hot water having a temperatue of 1 001C. The hot-rolled sheets 10 were then pickled and coldrolled so as to reduce the sheet thickness to 0. 30 mm. During cold-rolling, aging at a temperature of 2001C for 3 minutes was carried out between the cold-rolling passes.
Subsequently, decarburization annealing was carried out at a temperature of 8501C for 150 seconds in an atmosphere consisting of 75% hydrogen and 25% nitrogen and hav ' ing a dew point of 621C. An annealing separator consisting of a mixture of MgO and TiO, was appIlied on the decarburization annealed steel sheets and then final-annealing was carried out at a temperature of 1 2001C for 20 hours. Subsequently, a coating liquid, which was mainly composed of phosphoric acid, chromic acid anhydride, and aluminum phosphate, was applied on the final-annealed steel sheets, which were then subjected to flattening-annealing. The magnetic-properties and grain size of the final products (g), (h), and
(i) which were produced 20 using the ingots (g), (h), and (i), respectively, were measured. In addition, the appearance of the surface coating of each of the final products was determined.
The properties of the final products (g), (h), and (i) are given in Table 5.
7 GB 2 104 916 A 7 TABLE 5
Magnetic Properties Grain Size Appearance Final W1 7/50 of Surface Product B, (T) (W/Kg) ASTM No. x 1 Coating (g) 1.94 0.98 5 slightly thin (h) 1.94 0.96 5 good (i) 1.94 1.00 3.5 good properties.
The final product (h), in which the proportion of tin to copper was 1:0.6, exhibited the best EXAMPLE 4
The one ingot produced contained 0.085% of carbon, 3.2% of silicon, 0. 073% of manganese, 5 0.025% of acid-soluble aluminum, 0.0085% of nitrogen, 0.08% of tin, and 0. 07% of copper. The ingot was hot-rolled so as to obtain a hot-rolled sheet having a thickness of 2. 0 mm. Subsequently, precipitation-annea ling was carried out at 11 301C for 2 minutes, followed by rapid cooling in hot water having a temperature of 1 001C. The hot-rolled and precipitation-annealed sheet was pickled and col rolled so as to reduce the sheet thickness to 0.22 mm. During cold- rolling, aging at a temperature of 10 2501C was carried out for 5 minutes between the cold-rolling passes. Subsequently, decarburization annealing was carried out at a temperature of HO'C for 120 seconds in an atmosphere consisting of 75% hydrogen and 25% nitrogen and having a dew point of 620C. An annealing separator consisting of a mixture of MgO and TiO, was applied on the decarbu rization-a nnea led steel sheet, and final annealing was carried out at a temperature of 12000C for 20 hours. Then a coating liquid was applied on the resultant grain-oriented electromagnetic steel sheet. The grain size and the magnetic properties were as follows:
Grains size: ASTM No. 4.5 Magnetic flux density (B,): 1.92 tesia is Watt loss (W15150): 0.63 watts/kg 20 Watt loss (WMJ: 0.88 watts/kg

Claims (8)

1. A grain-oriented electromagnetic steel sheet or strip having a low watt loss and a high magnetic flux density, characterized in that it contains from 2.5% to less than 4. 0% of silicon, from 0.03% to less than 0.15% of manganese, from 0.03% to less than 0.5% of tin, and from 0. 02% to less than 0.3% of 25 copper, the remaining percentage being iron and unavoidable impurities.
2. A grain-oriented electromagnetic steel sheet or strip according to claim 1, characterized in that the proportion of tin to copper is in the range of from 1:0.5 to 1:1.
3. A grain-oriented electromagnetic steel sheet or strip according to claim 2, wherein said proportion of tin to copper is approximately 1:035.
4. A grain-oriented electromagnetic steel sheet or strip according to claim 1, wherein the tin content is from 0.05% to 0.2%.
5. A grain-oriented electromagnetic steel sheet or strip according to claim 1, wherein the copper content is from 0.05% to 0. 15%.
6. A process for producing a grain-oriented electromagnetic steel or strip having a low watt loss and a high magnetic flux density, characterized in that silicon material containing not more than 0.085% of carbon, from 2.5% to 4.0% of silicon, from 0.03% to 0.15% of manganese, from 0.010% to 0.050% of sulfur, from 0.010% to 0.050% of acid-soluble aluminum, and from 0. 0045% to 0.012% of nitrogen and additionally containing from 0.03% to 0.5% of tin and from 0.02% to 0. 3% of copper is hot-rolled, precipitation-a n nea led, cold-rolled at a final reduction ratio of not less than 65%, decarburization- 40 annealed, and final-annealed.
7. A process according to claim 6, wherein the decarburization-annealing conditions are: an annealing temperature of from 8001C to 900IC; holding the annealing temperature for from 30 8 GB 2 104 916 A 8 seconds to 10 minutes; and a protective atmosphere for annealing comprising wet hydrogen, nitrogen, or a mixture of wet hydrogen and nitrogen. 1
8. A process according to claim 6, wherein an annealing separator is applied on a decarburization annealed sheet and a coating liquid is applied on a final annealed sheet which is subsequently flattening annealed.
Printed for Her Majesty's Stationery Office by the Courier Press, Leamington Spa, 1983. Published by the Patent Office, 25 Southampton Buildings, London, WC2A lAY, from which copies may be obtained.
1
GB08222595A 1981-08-05 1982-08-05 Grain-oriented electromagnetic steel sheet and process for producing the same Expired GB2104916B (en)

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Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO1993001325A1 (en) * 1991-07-12 1993-01-21 Pohang Iron & Steel Co., Ltd. Grain oriented electrical steel sheet having superior magnetic properties, and manufacturing process thereof
US5415703A (en) * 1988-12-22 1995-05-16 Nippon Steel Corporation Very thin electrical steel strip having low core loss and high magnetic flux density and a process for producing the same

Families Citing this family (22)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS59185726A (en) * 1983-04-06 1984-10-22 Nippon Steel Corp Production of grain-oriented electrical steel sheet having excellent iron loss characteristics
JPS59185725A (en) * 1983-04-07 1984-10-22 Nippon Steel Corp Production of grain-oriented electrical steel sheet having excellent magnetic characteristic
JPS60177132A (en) * 1984-02-24 1985-09-11 Nippon Steel Corp Production of grain oriented electrical steel sheet having excellent magnetic characteristic and high magnetic flux density
EP0193324B1 (en) * 1985-02-22 1989-10-11 Kawasaki Steel Corporation Extra-low iron loss grain oriented silicon steel sheets
EP0184891B1 (en) * 1985-03-05 1989-07-12 Nippon Steel Corporation Grain-oriented silicon steel sheet and process for producing the same
JPH0621170B2 (en) * 1986-03-25 1994-03-23 ダイアホイルヘキスト株式会社 Biaxially stretched polyester film
JPH0768580B2 (en) * 1988-02-16 1995-07-26 新日本製鐵株式会社 High magnetic flux density grain-oriented electrical steel sheet with excellent iron loss
JPH0230740A (en) * 1988-04-23 1990-02-01 Nippon Steel Corp High magnetic flux density grain oriented electrical steel sheet having drastically excellent iron loss and its manufacture
JPH0215143A (en) * 1988-06-30 1990-01-18 Aichi Steel Works Ltd Soft magnetic stainless steel for cold forging
US5759293A (en) * 1989-01-07 1998-06-02 Nippon Steel Corporation Decarburization-annealed steel strip as an intermediate material for grain-oriented electrical steel strip
JPH0774388B2 (en) * 1989-09-28 1995-08-09 新日本製鐵株式会社 Method for manufacturing unidirectional silicon steel sheet with high magnetic flux density
US5047750A (en) * 1990-03-09 1991-09-10 Hector Larry F Non-intrusive infant security system
DE4311151C1 (en) * 1993-04-05 1994-07-28 Thyssen Stahl Ag Grain-orientated electro-steel sheets with good properties
AU2698897A (en) * 1997-04-16 1998-11-11 Acciai Speciali Terni S.P.A. New process for the production of grain oriented electrical steel from thin slabs
JP2006501361A (en) * 2002-05-08 2006-01-12 エイケイ・プロパティーズ・インコーポレイテッド Continuous casting method of non-oriented electrical steel strip
US20050000596A1 (en) * 2003-05-14 2005-01-06 Ak Properties Inc. Method for production of non-oriented electrical steel strip
US20050183797A1 (en) * 2004-02-23 2005-08-25 Ranjan Ray Fine grained sputtering targets of cobalt and nickel base alloys made via casting in metal molds followed by hot forging and annealing and methods of making same
JP4823719B2 (en) 2006-03-07 2011-11-24 新日本製鐵株式会社 Method for producing grain-oriented electrical steel sheet with extremely excellent magnetic properties
WO2010029921A1 (en) 2008-09-10 2010-03-18 新日本製鐵株式会社 Directional electromagnetic steel plate manufacturing method
KR101346537B1 (en) 2009-04-06 2013-12-31 신닛테츠스미킨 카부시키카이샤 Method for treating steel for directional electromagnetic steel plate and method for producing directional electromagnetic steel plate
JP7307354B2 (en) 2018-06-21 2023-07-12 日本製鉄株式会社 Grain-oriented electrical steel sheet with excellent magnetic properties
EP4202066A1 (en) 2021-12-21 2023-06-28 Thyssenkrupp Electrical Steel Gmbh Method for producing a grain-oriented electrical strip, cold-rolled steel strip and grain-oriented electrical strip

Family Cites Families (27)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR1054356A (en) * 1952-01-25 1954-02-10 Armco Int Corp Manufacturing process of silicon steel for magnetic applications
US2867557A (en) * 1956-08-02 1959-01-06 Allegheny Ludlum Steel Method of producing silicon steel strip
GB873149A (en) * 1956-11-08 1961-07-19 Yawata Iron & Steel Co Method of producing oriented silicon steel
US3239332A (en) * 1962-03-09 1966-03-08 Fuji Iron & Steel Co Ltd Electric alloy steel containing vanadium and copper
US3438820A (en) * 1965-04-02 1969-04-15 Dominion Foundries & Steel Silicon steel process
US3873380A (en) * 1972-02-11 1975-03-25 Allegheny Ludlum Ind Inc Process for making copper-containing oriented silicon steel
US3770517A (en) * 1972-03-06 1973-11-06 Allegheny Ludlum Ind Inc Method of producing substantially non-oriented silicon steel strip by three-stage cold rolling
US3855018A (en) * 1972-09-28 1974-12-17 Allegheny Ludlum Ind Inc Method for producing grain oriented silicon steel comprising copper
US3855020A (en) * 1973-05-07 1974-12-17 Allegheny Ludlum Ind Inc Processing for high permeability silicon steel comprising copper
JPS5413846B2 (en) * 1973-06-18 1979-06-02
JPS5432412B2 (en) * 1973-10-31 1979-10-15
US3929522A (en) * 1974-11-18 1975-12-30 Allegheny Ludlum Ind Inc Process involving cooling in a static atmosphere for high permeability silicon steel comprising copper
US4032366A (en) * 1975-05-23 1977-06-28 Allegheny Ludlum Industries, Inc. Grain-oriented silicon steel and processing therefor
US4046602A (en) * 1976-04-15 1977-09-06 United States Steel Corporation Process for producing nonoriented silicon sheet steel having excellent magnetic properties in the rolling direction
JPS53134722A (en) * 1977-04-28 1978-11-24 Nippon Steel Corp Material for high magnetic flux and uni-directional magnetic steel plate
ZA783651B (en) * 1977-07-01 1979-06-27 Lucas Industries Ltd Starter motor
JPS5432412A (en) * 1977-08-16 1979-03-09 Mitsui Petrochem Ind Ltd Purification of ketone
US4113529A (en) * 1977-09-29 1978-09-12 General Electric Company Method of producing silicon-iron sheet material with copper as a partial substitute for sulfur, and product
DE2834035A1 (en) * 1977-09-29 1979-04-12 Gen Electric METHOD FOR PRODUCING GRAIN ORIENTED SILICON IRON FLAT MATERIAL AND COLD-ROLLED SILICON IRON FLAT MATERIAL AS PRODUCT
JPS5429182A (en) * 1977-12-15 1979-03-05 Ntn Toyo Bearing Co Ltd Device for forming pocket bores in ring
US4123299A (en) * 1978-09-29 1978-10-31 General Electric Company Method of producing silicon-iron sheet materal, and product
DE2841961A1 (en) * 1978-10-05 1980-04-10 Armco Inc METHOD FOR PRODUCING GRAIN-ORIENTED SILICON STEEL
US4244757A (en) * 1979-05-21 1981-01-13 Allegheny Ludlum Steel Corporation Processing for cube-on-edge oriented silicon steel
US4367100A (en) * 1979-10-15 1983-01-04 Allegheny Ludlum Steel Corporation Silicon steel and processing therefore
US4338144A (en) * 1980-03-24 1982-07-06 General Electric Company Method of producing silicon-iron sheet material with annealing atmospheres of nitrogen and hydrogen
JPS5948935B2 (en) * 1981-08-05 1984-11-29 新日本製鐵株式会社 Manufacturing method of low iron loss unidirectional electrical steel sheet
JPH0415644A (en) * 1990-05-09 1992-01-21 Konica Corp Novel photographic coupler

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5415703A (en) * 1988-12-22 1995-05-16 Nippon Steel Corporation Very thin electrical steel strip having low core loss and high magnetic flux density and a process for producing the same
WO1993001325A1 (en) * 1991-07-12 1993-01-21 Pohang Iron & Steel Co., Ltd. Grain oriented electrical steel sheet having superior magnetic properties, and manufacturing process thereof

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GB2104916B (en) 1985-09-18
JPS6048886B2 (en) 1985-10-30
JPS5823414A (en) 1983-02-12
DE3229295A1 (en) 1983-03-03
FR2511045A1 (en) 1983-02-11
DE3229295C2 (en) 1986-09-18
US4863532A (en) 1989-09-05
US4753692A (en) 1988-06-28
BE894039A (en) 1982-12-01
FR2511045B1 (en) 1984-07-20

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